Saturday 6 April 2024

Hymenoptera plus.

I sometimes volunteer to identify various things for other folk. In my slightly laughable role as Ichneumonoidea recorder for the county (laughable because I'm really not very good at identifying them), I feel duty bound if someone finds something interesting. Anyway, back on 09/03/2024 MR found an Ichneumon in his garden which he posted on the FB Group and MS volunteered an ID of Syspasis lineator. This was a suggested ID not a nailed down, definitive identification. I was away at the time but asked MR to save the specimen, which he did. A quick look on NBN suggested there might not be Scottish records of this species, indeed the NBN hold just ten records of this species with the most northerly just SE of York. (This does not necessarily reflect the real distribution of this species but, all the same.)

When I got back from south I picked up the wasp and stuck it in the fridge. I had some other ID jobs in hand. However, yesterday and today have been the time to examine and key. Many thanks to MS and AR for getting me started and pointing me to the correct keys. Follows all my images of the beast:

Syspasis lineator, female.

The unbroken antenna has 37 flagomeres, and the 8th flagomere is partially pale, fully pale are 9, 10, 11 and 12, then the 13th is partially pale. The animal is 12.1mm head to apex of abdomen (excluding antennae). the first flagomere is x3.1 longer than wide measured at the widest point.

This Ichneumon parasitises Magpie Moth Abraxas grossulariata, a moth that has become established in Orkney relatively recently, indeed the first record was as recent as 22 July 1981 and by the end of 1991 it was still considered to be a rare migrant, there were just seven records and no larvae had been found. Currently the species is one of the commonest moths we catch, in some years, hundreds can come to a light trap in a single night. An interesting example of the parasitoid following its host.

The other hymenopteran of particular interest is a sawfly that I found in the drinking troughs (old baths and a tub) by the Burn of Layane below Kingshouse, on 31 March, very early for Orkney. With some help I got to Dolerus but that's when the fun started. Again help was enlisted online and AM, JS, IA and AG all gave advice. Eventually, it keyed out to Dolerus coracinus which is certainly new for Orkney and quite likely new for Scotland as well.

Dolerus coracinus.

I've been busy with other stuff as well, including finally deciding that I had to prove which species of bristletail are so common in the garden. These are not a particularly easy ID, although I strongly suspected Petrobius maritimus I'd never taken the time to nail this.

Photos were taken, specimens were taken and microscopic examination eventually proved the point, thanks to RC for pointing me to the key.

Petrobius maritimus.

You need a male to do these, annoyingly the key doesn't show the difference between males and females (a not unusual, but very annoying feature of many keys). And to make matters worse the feature that separates P. maritimus from P. brevistylis looks the same on the female of P.maritimus as on the male of P. brevistylis, doh!

Moths have been caught, it's early. Clearing out the shed produced a lot of Depressaria radiella and a Agonopterix that turned out to be a female heracliana, quelle supris! However, an Agonopterix found in a puddle this week got me going as a possibe A. ciliella, but I'm pretty sure it is just another heracliana. Quite a few Common Quaker, a few Clouded Drab and a Hebrew Character came to light. Louise saw two Emperor Moths in the garden and I caught a Common Quaker to LEEK pheromone. 

Clouded Drab

Common Quaker, male

Depressaria radiella

Female gendet, Agonopterix heracliana.

Washed out Agonopterix found alive in a pool.

Aedaegus; A. heracliana, I think.

I think this photo nails it as A. heracliana, male, as the cuiller, distal process of the sacculus, is not twisted. Females are harder to dissect successfully, but easier to determine once dissected.

There's a pile of other stuff, particularly beetles, including a couple of interesting ones found today. And on the bird front, Curlew have dispersed to territory, Snipe are singing and Black-tailed Godwits moving through, but more of that in the next post maybe.

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